Softpedia - Superconductors are a class of materials that display exactly zero electrical resistance and the exclusion of the interior magnetic field (the Meissner effect) at extremely low temperatures, usually below -140 degrees Celsius. They are used in many applications, like MRI medical imaging scanners, levitating trains and power lines. A team of researchers at the University of British Columbia achieved a breakthrough in the field. The most important problem of superconductors is the fact that they can't function at temperatures higher than 100 degrees Celsius below zero. "Up to now, it was unclear whether these materials were metals or insulators," said UBC Physics Prof. Douglas Bonn, adding that the materials are extremely sensitive to contamination - the slightest trace of dirt or impurity can alter their properties completely.